arm64: dts: rockchip: enable DC charger detection pullup on Pinebook Pro

On the Pinebook Pro the DC charger is detected via an open collector
transistor attached to a GPIO. This GPIO requires its pullup to be
enabled for the detection to work reliably.

Fixes: 5a65505 ("arm64: dts: rockchip: Add initial support for Pinebook Pro")
Signed-off-by: Tobias Schramm <t.schramm@manjaro.org>
Link: https://lore.kernel.org/r/20200414163952.1093784-3-t.schramm@manjaro.org
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

[ upstream commit: 7a87adb ]

src/arm64/rockchip/rk3399-pinebook-pro.dts

@@ -788,7 +788,7 @@
 
 	dc-charger {
 		dc_det_gpio: dc-det-gpio {
-			rockchip,pins = <4 RK_PD0 RK_FUNC_GPIO &pcfg_pull_none>;
+			rockchip,pins = <4 RK_PD0 RK_FUNC_GPIO &pcfg_pull_up>;
 		};
 	};